\documentclass{article}
\begin{document}

\section{Section One}
\label{sec:section_1}

This is the first equation:
\begin{equation}
1 + 1 = 2.
\label{eq:1}
\end{equation}

This is the second equation:
\begin{equation}
1 \times 1 = 1.
\label{eq:2}
\end{equation}

\end{document}
